What do Amino Acids Do? Sutton

Valine, leucine and isoleucine are considered 'essential' amino acids because they need to be present in your diet - as opposed to 'non-essential' amino acids, which your body can produce itself. Amino acids help stop your body breaking down muscle tissue, but what else do they do?

What do Amino Acids Do?

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What are they?BCAA (branched-chain amino acids) supplements contain valine, leucine and isoleucine. These are considered 'essential' amino acids because they need to be present in your diet - as opposed to 'non-essential' amino acids, which your body can produce itself. Together, they can comprise up to one-third of muscle protein.

What do they do? The theory is that they can help prevent the breakdown of muscle tissue during intense exercise. They also increase the release of human growth hormone.

Who should take them? 'BCAAs should be taken by anyone who weight trains,' says Gregg Marsh, 'preferably in capsule form rather than tablet or liquid.' There's little evidence that BCAAs will improve performance among endurance athletes, though, and unless you're training seriously hard it's possible you can get enough BCAAs from a recovery drink to make a separate supplement unnecessary.

How much should I take? 'Anything less than 20 capsules per workout is a waste of time,' says Marsh. 'Many professional rugby and football clubs have seen huge improvements in performance, using 40 caps of BCAAs every workout.' Anita Bean is more conservative: 'Doses of 6-15g may help improve your recovery during hard training periods.'

When should I take them? 'They work best if taken pre, during and post-workout,' says Marsh, 'Studies have shown that taking BCAA supplements during and after exercise can reduce muscle breakdown, and, taken before resistance training, reduce delayed onset muscle soreness.' They might also be beneficial if taken last thing at night - but the evidence here is sketchier.

Do they have any side effects?BCAAs are fairly safe, since you'd normally find them in protein in your diet anyway. Excessive intake might reduce the absorption of other amino acids, but that's about it.

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